Press Release
U.S. Fish and Wildlife Service Clamps Down on the Illegal Mitten Crab Trade

Today, the U.S. Fish and Wildlife Service announced the completion of Operation Mitten Catcher, an international law enforcement investigation that prevented the illegal import of approximately 15,525 live Chinese mitten crabs into the U.S.

Mitten crabs are considered a culinary delicacy in Asia and are smuggled into the U.S. in mass quantities in preparation for Chinese New Year and other cultural events. With the assistance of U.S. Customs and Border Protection and Environment and Climate Change Canada, Service wildlife inspectors seized the crabs at U.S. express hubs and major international airports. Smugglers had falsely declared the shipments as 100% polyester gowns, plastic molds, plastic storage bags and other commercial products.

“Chinese mitten crabs pose a significant threat to humans, the environment and our economy,” said Edward Grace, Assistant Director of the Service’s Office of Law Enforcement. “I would like to thank U.S. Customs and Border Protection and Environment and Climate Change Canada for their assistance with this operation. Together, we can help combat invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.

Learn more about invasive species
and end the illegal wildlife trade.”

Chinese mitten crabs are one of North America’s most invasive species and pose a serious threat to humans and the environment. In high densities, they can cause a number of problems including out‐competing native species for food and space; undermining flood levees; causing stream bank erosion; clogging screens, pumps and water intake structures at fish collection facilities and power plants; and hurting commercial and recreational fishing industries by consuming bait, damaging fishing nets and devouring catch. 

The species is also a carrier of Oriental lung fluke, a parasitic disease that can be transferred to humans in raw or undercooked crab meat. Fortunately, the Service works with specialists who test seized species for disease and the fluke has not yet been found in mitten crabs collected within the U.S.

“Our agriculture specialists and officers work closely with other federal agencies to protect our natural resources,” said Barbara Hassan, Supervisory Agriculture Specialist for U.S. Customs and Border Protection at the Port of Cincinnati. “In this case, cooperative efforts with the U.S. Fish and Wildlife Service prevented the introduction of a highly invasive and destructive species into our ecosystem.”

In 1989, the Service listed all mitten crabs of the genus Eriocheir, as well as their viable eggs, as injurious under the Lacey Act. Under the Lacey Act, it is illegal to import, export, sell, acquire or purchase live mitten crabs and other injurious wildlife without a permit. Violations are punishable by up to six months in prison and fines are as high as $5,000 for individuals or $10,000 for organizations.

In the U.S, mitten crabs have spread to California waterways, the Chesapeake and Delaware bays and the St. Lawrence Seaway. The crabs were introduced either intentionally to create a future food supply or accidentally through the discharge of contaminated ship ballast water. Female mitten crabs are capable of producing 250,000 - 1,000,000 eggs per brood and crabs can migrate up to 11 miles per day.

Operation Mitten Catcher is the second national inspection operation initiated by the Service’s Wildlife Inspection Interdiction Team. The team consists of seasoned Service law enforcement professionals who are committed to closing international wildlife trafficking pathways, generating intelligence and coordinating national wildlife inspection efforts.

If you suspect someone is illegally importing live mitten crabs or any other species, please call the Service’s wildlife trafficking tips line at 1-844-FWS-TIPS (397-8477) or email You might be eligible for a financial reward if your tip helps solve a case.

More information on how to report wildlife crime is available here: Refuge Law Enforcement.

You can help protect native ecosystems from mitten crabs, and other aquatic invaders, by:

  • Cleaning your boat and all of your gear (including waders and boots) after each use.
  • Draining all of the water from your boat before leaving the area.
  • Drying your gear completely (at least 48 hours) after each use.